This invention relates to the art of control circuits and, more particularly, to control circuits for automatically disconnecting a load from a voltage source when a predetermined condition is sensed. The invention is particularly applicable to use with electric motors and will be described with specific reference to electric motors. However, it will be appreciated that the invention has broader aspects and can be used with other electrically operated devices.
It is common to provide automobiles with motor-operated devices such as power windows, power antennas, power seats and power sun roofs. Control circuits for such motors commonly use mechanical current relays that are sensitive to vibration and voltage variations and do not provide overload protection. In such a case, a separate device must be provided for overload protection.
It would be desirable to provide a reliable control circuit having decreased sensitivity to vibration and voltage variations, while also providing overload protection.